Swift is now the de-facto official programming language for iOS app development. It has been created by Apple, keeping several considerations in mind. When back in 2014, Swift was introduced by Apple as the programming language that would change several paradigms for iOS development and will emerge as the only language to be used by iOS developers. There can hardly be any doubt that the prediction has come true, and Swift did and become what it promises to do and become.
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Swift has not just been a success story, but it generated countless success stories and played a crucial role in shaping the dominance of the Apple App Store and the iOS ecosystem in all these years. With every subsequent update, Swift continued to get better and more equipped and will continue to offer more value additions for Swift app developers in the years to come. So, it doesn't need any expertise that the future of iOS development is intertwined with the evolution of Swift.